Department of Cardiology, Faculty of Medicine, Bezmialem Foundation University, Istanbul, Turkey.
Med Sci Monit. 2013 Aug 23;19:696-702. doi: 10.12659/MSM.889511.
QT dispersion (QTd), which is a measure of inhomogeneity of myocardial repolarization, increases following impaired myocardial perfusion. Its prolongation may provide a suitable substrate for life-threatening ventricular arrhythmias. We investigated the changes in QTd and heart rate variability (HRV) parameters after successful coronary artery revascularization in a patient with chronic total occlusions (CTO).
MATERIAL/METHODS: This study included 139 successfully revascularized CTO patients (118 men, 21 women, mean age 58.3±9.6 years). QTd was measured from a 12-lead electrocardiogram and was defined as the difference between maximum and minimum QT interval. HRV analyses of all subjects were obtained. Frequency domain (LF: HF) and time domain (SDNN, pNN50, and rMSSD) parameters were analyzed. QT intervals were also corrected for heart rate using Bazett's formula, and the corrected QT interval dispersion (QTcd) was then calculated. All measurements were made before and after percutaneous coronary intervention (PCI).
Both QTd and QTcd showed significant improvement following successful revascularization of CTO (55.83±14.79 to 38.87±11.69; p<0.001 and 61.02±16.28 to 42.92±13.41; p<0.001). The revascularization of LAD (n=38), Cx (n=28) and RCA (n=73) resulted in decrease in HRV indices, including SDDN, rMSSD, and pNN50, but none of the variables reached statistical significance.
Successful revascularization of CTO may result in improvement in regional heterogeneity of myocardial repolarization, evidenced as decreased QTcd after the PCI. The revascularization in CTO lesions does not seem to have a significant impact on HRV.
QT 离散度（QTd）是心肌复极不均一性的指标，在心肌灌注受损后会增加。其延长可能为致命性室性心律失常提供合适的基质。我们研究了慢性完全闭塞（CTO）患者成功冠状动脉血运重建后 QTd 和心率变异性（HRV）参数的变化。
材料/方法：本研究纳入 139 例成功血运重建的 CTO 患者（男 118 例，女 21 例，平均年龄 58.3±9.6 岁）。QTd 从 12 导联心电图测量，定义为最大 QT 间期和最小 QT 间期之差。对所有患者进行 HRV 分析。分析频域（LF：HF）和时域（SDNN、pNN50 和 rMSSD）参数。QT 间期也用 Bazett 公式校正心率，然后计算校正 QT 间期离散度（QTcd）。所有测量均在经皮冠状动脉介入治疗（PCI）前后进行。
CTO 成功血运重建后 QTd 和 QTcd 均显著改善（55.83±14.79 至 38.87±11.69；p<0.001 和 61.02±16.28 至 42.92±13.41；p<0.001）。LAD（n=38）、Cx（n=28）和 RCA（n=73）的血运重建导致 HRV 指数包括 SDNN、rMSSD 和 pNN50 下降，但均无统计学意义。
CTO 成功血运重建后可能导致心肌复极区域性异质性改善，PCI 后 QTcd 降低。CTO 病变血运重建似乎对 HRV 没有显著影响。
